• 한국전산구조공학회논문집
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• 제19권3호
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• pp.239-245
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• 2006

본 연구에서는, 지진하중에 의해 구조물에 발생하는 진동을 제어하기 위하여 토글 시스템의 비선형성을 연구하고, 자기유변유체(MR) 감쇠기를 장착한 토글 가새시스템의 성능을 평가하였다. Bingham 모델로 표현되는 MR감쇠기의 제어력이 속도의 함수인 점을 고려하여, 토글 가새시스템에 의한 속도증폭계수를 계산하였고 토글 형태에 대한 증폭계수효과를 평가하였다. 특히 강한 지진하중에서 쉐브론과 대각가새 등의 전형적인 가새시스템에 장착된 MR감쇠기가 충분한 응답감소효과를 제공하지 못하는 경우에, 토글 가새시스템을 사용하여 제어성능을 크게 강화시키는 것을 수치해석 결과를 통하여 확인하였다.

• 대한기계학회논문집B
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• 제33권7호
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• pp.520-526
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• 2009

The objectives of this paper are to measure the heat transfer and pressure drop of the plate heat exchangers for absorption system applications. Three types of plate heat exchangers with different chevron angles are tested in the present experiment. Heat transfer and pressure drop performance of plate heat exchangers are measured in various operating conditions, and compared each other. The results show that the heat transfer rate of high theta ($120^{\circ}$) and mixed theta plate heat exchanger increases about 118% and 98% at the solution flow rate 350 kg/h compared to that of low theta ($60^{\circ}$), respectively. The effectiveness of high theta was evaluated about $0.53{\sim}0.85$ in this experimental range. The experimental correlations of the Nu and f were developed with error bands of ${\pm}7%$ and ${\pm}12%$.

• 설비공학논문집
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• 제23권8호
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• pp.535-542
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• 2011

The performance of a plate heat exchanger for using liquid solution in the absorption chiller-heater was analyzed. The model was developed by using the various performance prediction correlations. The performance characteristics of the plate heat exchanger with the mass flow rate ratio was verified by using experimental data. To investigate performance of plate heat exchanger with geometry variables, the chevron angle, corrugated wave length, and corrugation depth were changed. As a result, the capacity of Kim and Martin correlation models was similar with the experimental data, and the capacity difference was less than 2%. Besides, the pressure drop of Marin correlation model showed a similar variation with experimental data, and the difference of pressure drop was less than 1.5 kPa.

• 대한족부족관절학회지
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• 제13권2호
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• pp.124-128
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• 2009

Purpose: The authors intended to analyze the operative results of mild to moderate hallux valgus treated with distal chevron metatarsal osteotomy. Materials and Methods: Twenty six feet of twenty three patients were followed for more than 1 year after the distal chevron metatarsal osteotomy. Biplanar osteotomy with wedge resection was done when the distal metatarsal articular angle (DMAA) was increased. The mean age was 39 years, and the mean follow up period was 27 months. Clinically preoperative and postoperative AOFAS hallux MP-IP scale and satisfaction after the surgery were analyzed. Radiologically hallux valgus angle, the 1st intermetatarsal angle, DMAA and sesamoid position before and after the operation were analyzed. Results: Distal chevron osteotomy was done in 15 cases and biplanar osteotomy was done in 11 cases. Clinically AOFAS scale was increased from 65.3 points preoperatively to 92.2 points postoperatively. Two patients were not satisfied with the results. Radiologically hallux valgus angle was decreased from $21.9^{\circ}$ preoperatively to $8.5^{\circ}$ postoperatively. The first intermetatarsal angle was decreased from $11.8^{\circ}$ preoperatively to $6.7^{\circ}$ postoperatively. DMAA was decreased from $11.8^{\circ}$ preoperatively to $5.5^{\circ}$ postoperatively. There was one case of minor wound infection. Conclusion: Distal chevron metatarsal osteotomy appears to be safe and satisfactory procedure for mild to moderate hallux valgus.

• 한국산학기술학회논문지
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• 제21권2호
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• pp.528-534
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• 2020

판형 열교환기의 초기 개발 및 사용은 19세기 후반 유제품 내 존재하던 각종 바이러스의 살균에 대한 엄격한 법규 대응을 위해 시작되었고, 1920년대가 되어서야 본격적으로 상업화되었다. 이후 판형 열교환기의 기본 컨셉은 지금까지도 거의 변화가 없었지만, 고온, 고압 그리고 대용량 열교환에 적용되기 위해 설계 및 제작 방법들이 혁신적으로 발전하여 지금에 이르게 되었다. 현재의 형태와 같은 쉐브론 타입 주름 전열판의 개발은 1970년대 후반 오일 쇼크 이후 에너지 합리화 및 에너지 효율 향상을 위한 요구들이 강하게 제기되면서 시작되어 지금에 이르고 있다. 판형 열교환기의 개발 트렌드는 전열 효율이 좋으면서 압력강하가 낮고 또한 유체 분배가 잘되는 대형 전열판의 개발과 일치한다. 본 논문에서는 전열판 개발방향을 제시하고자 동일 골깊이와 주름피치를 가진 소형 전열판과 대형 전열판의 열성능을 각 채널(H, M, L type)별로 실험적으로 비교, 분석하였다. 실험결과, 대류열전달계수의 경우, 소형 전열판이 대형 전열판에 비해 H type의 경우 평균 16.5%, M type의 경우 25%, 그리고 L type의 경우 약 40% 정도 더 높았다. 압력강하의 경우는 소형 전열판이 H type의 경우 평균 19%, M type의 경우 46%, 그리고 L type의 경우 약 61% 정도 더 높은 것을 알 수 있었다. 이는 여러 예상되는 요인들 중 두 전열판의 유체분배부 차이에 의한 것으로 판단되었다.

• 한국중재학회지:중재연구
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• 제25권4호
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• pp.3-23
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• 2015

The Chevron saga including Chevron/TexPet v. Ecuador, PCA Case No. 34877(hereinafter referred to as "Chevron I") and Chevron/TexPet v. Ecuador, PCA Case No. 2009-23(hereinafter referred to as "Chevron II") started out of domestic litigations between TexPet and Ecuador in the early 1990s. In Chevron I, the Tribunal decided that Article 2(7) of the U.S.-Ecuador BIT on effective means of provision was breached because of undue delays in the seven legal proceedings TexPet had brought against Ecuador in respect to contractual obligations. In Chevron II, it was contended that through the actions and inactions of the judiciary and the executive, Ecuador breached her several obligations under the BIT. Ecuador objected to the jurisdiction of the Tribunal because TexPet's investment was terminated in 1992, and because Chevron is not a party to the 1995 Settlement Agreement and 1998 Final Release. In its Interim Award on Jurisdiction and Admissibility, the Tribunal applied a prima facie standard to the facts alleged by the Claimants but denied by the Respondent, and decided that questions in respect of the Respondent's jurisdictional objections should be joined to the merits under Article 21(4) of the UNCITRAL Arbitration Rules. In the merits phase of Chevron II, the Tribunal divided the merits of the Parties' dispute into two parts, entitled "Track 1" and "Track 2". In its Partial Award on Track 1, the Tribunal decided that Chevron is a "Releasee" under the 1995 Settlement Agreement. In a decision on "Track 1B", the Tribunal decided that the Lago Agrio complaint cannot be read as pleading "exclusively" or "only" diffuse claims, and that, to this extent, the Claimants' reliance on the 1995 Settlement Agreement as a complete bar to the Lago Agrio complaint must fail, as a matter of Ecuadorian law. The Tribunal maintained the position that the Parties' disputes on both merit and jurisdiction should be reserved for Track 2. It remains to be seen how the Tribunal addresses the Claimants' allegations of multiple denials of justice under international law against the judgments of the Respondent's Courts, together with the Respondent's jurisdictional objections in Track 2 of the arbitration.